Such devices are generally known as "hip screws". One such device is disclosed in German Patent Application No. A 41 06 876. The anchor screw disclosed in this application has only a single thread. U.S. Pat. No. 5,269,686 discloses a dental implant with a four-thread screw. However, the use of this dental implant for internal fixation of long bones is not taught or suggested. Finally, a femoral nail with a rotationally stable femoral neck screw is known from European Patent Application A 0 257 118. However, the nail only has a single thread.
All known prior art designs of hip screws suffer from the same disadvantage. Specifically, implantation causes substantial bone loss. As a result, any required revision surgery or subsequent second intervention is very difficult due to loss of bone. Thus, there exists a need for an improved hip screw.